Collective excitations and tunneling dynamics in long bosonic Josephson junctions

Momme, M. R.; Bidasyuk, Y. M.; Weyrauch, M.

doi:10.1103/physreva.100.033601

Cited by 8 publications

(12 citation statements)

References 35 publications

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“…[19] and their theoretical investigation reported in Refs. [20][21][22][23][24][25][26][27][28][29][30][31]. Currentphase relations of atomic JJs were measured in Refs.…”

Section: Introductionmentioning

confidence: 99%

Josephson junction dynamics in a two-dimensional ultracold Bose gas

Singh

Luick

Sobirey

et al. 2020

Phys. Rev. Research

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We investigate the Berezinskii-Kosterlitz-Thouless (BKT) scaling of the critical current of Josephson junction dynamics across a barrier potential in a two-dimensional Bose gas, motivated by recent experiments by Luick et al. [Science 369, 89 (2020)]. Using classical-field dynamics, we determine the dynamical regimes of this system as a function of temperature and barrier height. As a central observable we determine the current-phase relation as a defining property of these regimes. In addition to the ideal junction regime, we find a multimode regime, a second-harmonic regime, and an overdamped regime. For the ideal junction regime, we derive an analytical estimate for the critical current, which predicts the BKT scaling. We demonstrate this scaling behavior numerically for varying system sizes. The estimates of the critical current show excellent agreement with the numerical simulations and the experiments. Furthermore, we show that the damping of the supercurrent is associated with the phonon excitations in the bulk, and the nucleation of vortex-antivortex pairs in the junction.

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“…[19] and their theoretical investigation reported in Refs. [20][21][22][23][24][25][26][27][28][29][30][31]. Currentphase relations of atomic JJs were measured in Refs.…”

Section: Introductionmentioning

confidence: 99%

Josephson junction dynamics in a two-dimensional ultracold Bose gas

Singh

Luick

Sobirey

et al. 2020

Phys. Rev. Research

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“…In particular, the tunneling of atoms through the barrier may be effectively coupled with their motion inside each condensate if corresponding collective modes posses similar energies. The signatures of such a coupling were previously identified in theoretical [15,17,25] and experimental studies [5]. Here we investigate these effects further by extracting and ana-lyzing the spectrum of collective excitations and building the dispersion relations of quasiparticle modes in parallel coupled elongated BECs.…”

Section: Introductionmentioning

confidence: 79%

“…One of the most simple yet nontrivial geometries is realized with two parallel cigarshaped condensates coupled through a potential barrier along their long dimension. This system has many similarities with superconducting long Josephson junctions [17,18]. It was also used to study the properties of sine-Gordon solitons and Josephson vortices in BECs [18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Dispersion relations and self-localization of quasiparticles in coupled elongated Bose-Einstein condensates

2020

Self Cite

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We present a detailed study of the spectrum and dispersion of Bogoliubov quasiparticles in two coupled elongated Bose-Einstein condensates. We develop an analytically solvable model that approximates two infinite homogeneous condensates and compare its predictions to a numerical simulation of a realistic trapped system. While the comparisons show a reasonable agreement between the two models, they also manifest the existence of several anomalous Bogoliubov modes in the spectrum. These modes show degeneracy in both energy and momentum together with self-localization in the coordinate space.

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“…In this paper, we study a simple example of such a setting-a pair of tunnel-coupled one-dimensional (1D) Bose gases in the quasicondensate regime. This system has already been studied extensively, both theoretically [8][9][10][11][12][13][14] and experimentally [15][16][17][18][19][20][21][22], in the scenario in which an initially single 1D quasicondensate was coherently split into two quasicondensates and allowed to relax through dephasing. In particular, in the experiment of Hofferberth et al [15], the authors observed a fast, subexponential decay of relative coherence in the completely decoupled case [23,24]; the dephasing between the two quasicondensate occurred on the order of milliseconds.…”

Section: Introductionmentioning

confidence: 99%

Dynamics of thermalization of two tunnel-coupled one-dimensional quasicondensates

Bayocboc,

Davis,

Kheruntsyan

2021

Preprint

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We study the non-equilibrium dynamics of two tunnel-coupled one-dimensional quasicondensates following a quench of the coupling strength from zero to a fixed finite value. More specifically, starting from two independent quasicondensates in thermal equilibrium, with initial temperature and chemical potential imbalance, we suddenly switch on the tunnel-coupling and analyse the postquench equilibration in terms of particle number and energy imbalances. We find that, in certain parameter regimes, the net energy can flow from the colder quasicondensate to the hotter one and is governed by the surplus of low energy particles flowing from the cold to the hot system relative to the high-energy particles flowing in the reverse direction. In all cases, the approach to the new thermal equilibrium occurs through transient, damped oscillations. We also find that for a balanced initial state the coupled quasicondensates can relax into a final thermal equilibrium state in which they display a thermal phase coherence length that is larger than their initial phase coherence length, even though the new equilibrium temperature is higher. The increase in the phase coherence length occurs due to phase locking which manifests itself via an increased degree of correlation between the local relative phases of the quasicondensates at two arbitrary points.

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Collective excitations and tunneling dynamics in long bosonic Josephson junctions

Cited by 8 publications

References 35 publications

Josephson junction dynamics in a two-dimensional ultracold Bose gas

Josephson junction dynamics in a two-dimensional ultracold Bose gas

Dispersion relations and self-localization of quasiparticles in coupled elongated Bose-Einstein condensates

Dynamics of thermalization of two tunnel-coupled one-dimensional quasicondensates

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